def main():
    n = int(input())

    s_set = set()
    for i in range(n):
        order = input().split()
        if order[0] == "insert":
            s_set.add(order[1])
        else:
            if order[1] in s_set:
                print("yes")
            else:
                print("no")


if __name__ == '__main__':
    main()
 def main():
    n = int(input())

    s_set = set()
    for i in range(n):
        order = input().split()
        if order[0] == "insert":
            s_set.add(order[1])
        else:
            if order[1] in s_set:
                print("yes")
            else:
                print("no") main n = int(input()) n int(input()) int input() input s_set = set() s_set set() set for i in range(n):
        order = input().split()
        if order[0] == "insert":
            s_set.add(order[1])
        else:
            if order[1] in s_set:
                print("yes")
            else:
                print("no") i range(n) range n order = input().split() order input().split() ().split () input split if order[0] == "insert":
            s_set.add(order[1])
        else:
            if order[1] in s_set:
                print("yes")
            else:
                print("no") order[0] == "insert" order[0] order 0 "insert" s_set.add(order[1]) s_set.add s_set add order[1] order 1 if order[1] in s_set:
                print("yes")
            else:
                print("no") order[1] in s_set order[1] order 1 s_set print("yes") print "yes" print("no") print "no" if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    n = int(input())

    s_set = set()
    for i in range(n):
        order = input().split()
        if order[0] == "insert":
            s_set.add(order[1])
        else:
            if order[1] in s_set:
                print("yes")
            else:
                print("no") def main():
    n = int(input())

    s_set = set()
    for i in range(n):
        order = input().split()
        if order[0] == "insert":
            s_set.add(order[1])
        else:
            if order[1] in s_set:
                print("yes")
            else:
                print("no") main
def main():
    n = int(input())

    s_set = set()
    for i in range(n):
        order = input().split()
        if order[0] == "insert":
            s_set.add(order[1])
        else:
            if order[1] in s_set:
                print("yes")
            else:
                print("no")


if __name__ == '__main__':
    main()

